Intercalation of alkali metals (Li, Na, K, Rb and Cs) into natural graphite flakesby the solvent method usingtetrahydrofuran (THF), 2-methyltetrahydrofuran (MeTHF) and 2, 5-dimethyltetrahydrofuran (diMeTHF) has beenstudied by X-ray diffractometry (XRD). Using THF as a solvent, ternary graphite intercalation compounds (GICs) withalkali metalsand the solvent are formed for all alkali metals. In the case of Li, however, situation is different; XRDpatterns of binary Li-GICs, which were observed in the early stage of thepreparation of Li-THF-GIC, disappeared asthe reaction time increased. In the Rb-THF solution, three types of ternary GICs with different Ic are formed by varyingthe preparation temperature. When MeTHF is used as a solvent, binary GICs are obtained for Li, Na and K, and bothbinary and ternary GICs are formed for Rb and Cs. In the case of diMeTHF solvent, only binary GICs are formed for all kinds of alkali metals except Na.